maculosus angelfish showing unusual buoyancy

[ss88]

Hello

I’m looking for guidance on a 8” maculosus angelfish showing unusual buoyancy and weight changes.

Background:

• Fish was placed into half salinity 2 months ago ~16 ppt
• 20 days ago began raising salinity
• Current salinity is: 24ppt
• This has been ongoing for 14 days.

Symptoms:

• Negatively buoyant (tends to sink, struggles to maintain position)
• Still actively eating
• Noticeable weight loss despite feeding
• Behavior and buoyancy issues only began once salinity started increasing, not during the lowest hypo point.
• I tend to only raise salinity at 1ppt per day.
• All other fish in the system are acting normal.

Additional notes:

• No obvious external signs of disease
• Issue appears progressive with salinity increase

Questions:

Does this pattern point more toward:

• Osmoregulatory stress from shifting salinity inducing a secondary swim bladder dysfunction?
• Or another underlying issue being exacerbated?

Treatment options.
From my prospective this appears to be kidney disfunction related to salinity changes. As a treatment option, I am considering removing the specimen and place back into half salinity to reduce osmotic stress.

Any insight on likely cause and best course of action would be greatly appreciated.


Thanks in advance.

 

[Jay Hemdal]

Hello

I’m looking for guidance on a 8” maculosus angelfish showing unusual buoyancy and weight changes.

Background:

• Fish was placed into half salinity 2 months ago ~16 ppt
• 20 days ago began raising salinity
• Current salinity is: 24ppt
• This has been ongoing for 14 days.

Symptoms:

• Negatively buoyant (tends to sink, struggles to maintain position)
• Still actively eating
• Noticeable weight loss despite feeding
• Behavior and buoyancy issues only began once salinity started increasing, not during the lowest hypo point.
• I tend to only raise salinity at 1ppt per day.
• All other fish in the system are acting normal.

Additional notes:

• No obvious external signs of disease
• Issue appears progressive with salinity increase

Questions:

Does this pattern point more toward:

• Osmoregulatory stress from shifting salinity inducing a secondary swim bladder dysfunction?
• Or another underlying issue being exacerbated?

Treatment options.
From my prospective this appears to be kidney disfunction related to salinity changes. As a treatment option, I am considering removing the specimen and place back into half salinity to reduce osmotic stress.

Any insight on likely cause and best course of action would be greatly appreciated.


Thanks in advance.

Can you post a video of the fish?

With fish in seawater, abrupt changes in salinity can cause temporary changes in the fish's buoyancy - lower salinity can cause the fish to sink, while a rise in salinity can make the fish temporarily more buoyant. However, these changes are usually mild, not everyone notices them, and they should be temporary.

Your fish is negatively buoyant despite the rising salinity, so something else seems to be going on here.....

 

[ss88]

 

[ss88]

A bit more context here I have been out of town for several weeks, so it’s possible something acute occurred. I have cameras in my systems to help monitor the specimens during my absence.

I made a salinity adjustment yesterday afternoon raising it approximately one or two parts per thousand, my thinking yesterday was that possibly a more normal salinity condition would help with osmotic regulation. Seems to have had the opposite effect. His condition today seems to have declined further. He does still have an interest in eating food but his appetite has further decreased. It appears that what ever underlying issue might be exacerbated by the salinity increase.

 

[Jay Hemdal]

A bit more context here I have been out of town for several weeks, so it’s possible something acute occurred. I have cameras in my systems to help monitor the specimens during my absence.

I made a salinity adjustment yesterday afternoon raising it approximately one or two parts per thousand, my thinking yesterday was that possibly a more normal salinity condition would help with osmotic regulation. Seems to have had the opposite effect. His condition today seems to have declined further. He does still have an interest in eating food but his appetite has further decreased. It appears that what ever underlying issue might be exacerbated by the salinity increase.

From the video, it sure seems like negative buoyancy due to an under-inflated swim bladder. I’m sorry, but I don’t know of any treatment for that.

I’m not sure what an acute cause for this might have been. I’ve always presumed that in physoclistus fish species, this is caused by a dysfunction in the gas gland.

 

[ss88]

Any idea what could’ve caused this. This is a relatively newly acquired specimen from December. The specimen has been through a standard 2.25 ppm copper treatment for 30 days followed by half salinity for fluke’s. Could this be related to the collection degassing of the swim bladder?

 

[Jay Hemdal]

Any idea what could’ve caused this. This is a relatively newly acquired specimen from December. The specimen has been through a standard 2.25 ppm copper treatment for 30 days followed by half salinity for fluke’s. Could this be related to the collection degassing of the swim bladder?

No - this species doesn’t need to be “de-gassed” after collection like deep water angelfish are. Also, when fish suffer from improper de-gassing, they float not sink.